I would like to make the lid as you would see on a real ring box, i.e. open and at more or less 90 degrees (see picture but pretend it's a hexagon!). Is this possible I ask myself? I was thinking of making a mould and laying thinly rolled petal paste panels over it until it has hardened. I'm not certain if the whole structure will be too heavy and/or fragile to stand up at 10" wide.

When you look at the lid of most ring boxes, they are dome shaped to accommodate the ring. I'd like mine to be as realistic as possible and will make my mould a dome shape. I'm going to have a practice in the next few days to see if I'm attempting the impossible

Has anyone here every tried anything similar? Can anyone give me any advice? I would be most grateful for any tips or dire warnings!

When you make your lid, roll your gumpaste out to about 3/16" (halfway between 1/8" and 1/4"). When you put it on your mold, place three or four skewers into the bottom edge of the lid, evenly spaced, sticking out toward what would be the body of the box once you're ready to assemble the cake. When you put it together, pipe a line of melted chocolate (or candy melts the same color as your box) along the edge of the lid where the skewers are sticking out. Insert the skewers into the side of the cake until the lid is where you want it. Hold it in place for a couple of minutes until the chocolae sets up. I've only done this on a 6" cake, so, if you have a chance, you might want to have a dry run with this technique before you actually do the cake.